Cairn stacks

A Cairn stack is one .cairn.html file. Inside it: the reader software, the optional visual editor, a card-based document stored as plain JSON, every picture and sound it needs, and the reader's place in it. Open it from a folder and it works — no server, no install, no network. Press Edit and the reader becomes an author. Press Save As and the browser writes a new file that carries all of that with it.

That constraint is the whole point, and it shapes authoring:

• Content is data, never code. No author CSS, no author JavaScript. Colour comes from eight theme tokens; behaviour comes from a small closed set of declarative actions. What you cannot express is deliberately out of reach.
• Everything is inside the file. Prefer sealed, which cannot reach the network at all. A stack that needs a CDN is a stack that dies with the CDN.
• Layout is absolute. A card is a fixed canvas — 1280 × 800 unless you choose otherwise — and every element is a positioned box. There is no flexbox to save you, which is why the grid below matters more here than in ordinary web work.